Worldwide spreading of economic crisis

We model the spreading of a crisis by constructing a global economic network and applying the Susceptible-Infected-Recovered (SIR) epidemic model with a variable probability of infection. The probability of infection depends on the strength of economic relations between the pair of countries, and the strength of the target country. It is expected that a crisis which originates in a large country, such as the USA, has the potential to spread globally, like the recent crisis. Surprisingly we show that also countries with much lower GDP, such as Belgium, are able to initiate a global crisis. Using the {\it k}-shell decomposition method to quantify the spreading power (of a node), we obtain a measure of ``centrality'' as a spreader of each country in the economic network. We thus rank the different countries according to the shell they belong to, and find the 12 most central countries. These countries are the most likely to spread a crisis globally. Of these 12 only six are large economies, while the other six are medium/small ones, a result that could not have been otherwise anticipated. Furthermore, we use our model to predict the crisis spreading potential of countries belonging to different shells according to the crisis magnitude.Comment: 13 pages, 4 figures and Supplementary Materia

Effect of degeneracy on Frenkel excitons in ordered and orientationally disordered columnar aggregates

The effect of the degeneracy of the molecular dipolar transitions on the properties (dispersion curves, oscillator strengths, absorption spectra) of Frenkel excitons in ordered helical and orientationally disordered columnar mesophases, characterized by strong interchromophore interactions and short stacking distance, is investigated through a model based on numerical calculations. It is shown that the degeneracy makes the optical spectra less sensitive to chromophore rotation and maintains the excitons carrying the oscillator strength quite delocalised even in the presence of complete orientational disorder

Degeneracy, orientational disorder and chromophore size effects on Frenkel excitons in columnar mesophases

The properties of Frenkel excitons in columnar mesophases are analysed using numerical calculations with a particular emphasis on the off-diagonal disorder induced by rotation of the molecular disks around the column axis. The influence of degeneracy of the molecular electronic transitions and the effect of the chromophore size are illustrated by means of the extended dipole model. The localisation/delocalisation behaviour of the exciton states is characterised by calculation of the participation ratio. It is shown that the existence of two orthogonal dipolar transitions per chromophore makes the optical spectra less sensitive to chromophore rotation and maintains the eigenstates bearing the oscillator strength quite delocalised, even in the presence of complete orientational disorder. 2001 Elsevier Science B.V. All rights reserved

Photophysica behaphy ofa homologous series ofa[H3B]S)[z hemicya)[z dyes in thin AOT films

The photophysica behaphy ofa homologous series ofaV3[3jS)jV hemicya)jV]4 incorporaV] in thin films,mas by dip-coajB[ glac slides in bis(2-ethylhexyl)sulfosuccinaB sodiumsai (AOT) reverse micella solutions,ha been studied byazVVVS)jH spectrophotometryap computersimulaSV] techniques. Atrela43S)j high dyeconcentrajHj4 a naonc bao in the aSBB3--HS) spectrumwa observed, corresponding toajVjV[S)V species.Aggregaj-- ag of the Htype, displaVzS a hypsochromic shift in theirairSVB[4V spectra except for the shortestchat homolog. The growth of aS[--344S) in films ha been studied inrela4Bj with the wa]3 #=dye#aj surfaS)V4 #=dye#raHVBB imulaBS) of the aheS[--3z forma--3z by extended dipoleinteraHV4] inspherica reverse micellesac plall bilale structures in combinaS)V withexperimenta dape reveaim tha the filmsam structured in microheterogeneousacroheter aarohet to the reverse micelles found in theorigina solutions. # 2002 Elsevier Science B.V. All rights reserved. 1.I oduction The properties ofaSBV44H lic hemic yaicS dyes isa subject of substaV]4S investiga tions beca se of their possible asible tions in optoelectronicsa d molecula electronic devices [1,2]. Their tendency toaS]Bj[ te [3,4]ha beena aenSB inLaV muir-- Blodgett filmsa dmonola ersa theaeSVBV er interfa3 in order to producemaB ria3 with nonlinea roptica properties [5,6]. DyeaeSB--V tes as as of pa[V[S)3z impor taor for photograVVH processa dxerogra phic reproductiona spectra sensitizers [7]. InaSj]4j4 to suchac lica[j4H , surfaS)Bz hemicya ines, with both dyeingae aeingS[ lic propertiesar suit ait components for studying photophysica phenomena sucha J- aSH-az rega-- formaj on [8]. Since these dyes hasa strong tendency to aS gregaz it isnecessa ry to understa[ thenaS[] of aS[--34 te form armS in order tofa[V ca[ a[V - bl..

A Kinetic Model for J-Aggregate Dynamics

this paper we make an attempt to construct a selfconsistent model of the 3,3-disulfopropyl-5,5-dichloro-thiacarbocyanine (THIATS) J-aggregate by simultaneous simulation of both the absorption and emission spectra, as well as the luminescence decay profile